[Feature] OIDC should be exported and available in libnpmpublish

The OIDC function from oidc.js is not currently exported neither available from the libnpmpublish package. This mean that to get it working in Lerna/Lerna-Lite (I maintain the latter), we had to copy and reimplement the oidc.js into Lerna/Lerna-Lite to make it work.

There's 2 obvious issues related to this approach:

1. duplicate code increasing Lerna/Lerna-Lite project size
2. any changes made in oidc.js needs to be resync manually in external projects like Lerna/Lerna-Lite
   • for example adding OIDC CircleCI support was added much later and this wasn't synched back to Lerna which means it doesn't currently work in Lerna (I did synch it myself in Lerna-Lite though)
   • ref: Lerna oidc.ts and Lerna-Lite oidc.ts
   • Lerna currently has an open issue related to their oidc being out of sync: https://github.com/lerna/lerna/issues/4358

libnpmpublish only exports 2 functions (publish and unpublish)

https://github.com/npm/cli/blob/455aa4a17b92a77ffbd474c4dc17a16f71cfe6b1/workspaces/libnpmpublish/lib/index.js#L1-L4

I mention Lerna/Lerna-Lite in here, but I'm sure there's few hundred projects that would benefit from having OIDC available directly in libnpmpublish

Start with workspaces/libnpmpublish/lib/index.js and the existing oidc.js implementation, then compare how libnpmpublish currently exposes publish and unpublish. Done means the OIDC function is available through the libnpmpublish package without downstream projects copying its implementation.